Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Interacting limit

State Vertical transition energy Relaxation energy  [Pg.219]

To investigate the combined effects of electron-lattice and electron-electron interactions we again employ the Pariser-Parr-Pople-Peierls model introduced in Section 7.2. Notice that the calculations described here do not describe free rotations of phenyl rings relative to one another. Thus, their applicability are to ladder poly(para-phenylene), where the stereochemistry causes the rings to have a planar geometry, or polymers in the solid state, where ring rotations are more restricted. [Pg.219]

2 71+ states for 4 and 8 ring para-phenylene oligomers. As in linear polyenes, the relaxation energy of the state is small, whereas the relaxation energy [Pg.219]

The l Bj state is now an exciton-polaron. Its structure is qualitatively similar in both the noninteracting and interacting limits, as the soliton-antisoliton confinement due to linear confinement arising from the effective extrinsic bond alternation has a rather similar effect to electron-hole attraction. However, as already predicted, the state has a more pronounced distortion because it [Pg.220]


Due to the linear Independence of occupation indices Tji the concentration-dependent parameters can be determined from the concentration-independent ones. In the special case of interactions limited to the fourth order and nearest neighbors one finds for fcc-based alloys... [Pg.40]

Research Opportunities. The presence of a long-lived fluorescing state following either 532 nm or 1064 nm excitation of PuF6(g) provides a valuable opportunity to study the extent to which electronic energy in a 5f electron state is available in photochemical and energy transfer reactions. Such gas phase bimolecular reactions would occur in a weak interaction limit governed by van der Waals forces. Seen from the perspective of potential photochemical separations in fluoride volatility... [Pg.171]

A statin combined with a resin results in similar reductions in LDL cholesterol as those seen with ezetimibe. However, the magnitude of triglyceride reduction is less with a resin compared to ezetimibe, and this should be considered in patients with higher baseline triglyceride levels. In addition, gastrointestinal adverse events and potential drug interactions limit the utility of this combination. [Pg.191]

In this complex, the energy gap 2J separating upper and lower potential surfaces is estimated to be 0.19 eV. This is evidently too large for the weak-interaction limit to hold. In other systems, J may, in fact, become so large that we have a single minimum, with a stationary delocalized electronic ground state. [Pg.308]

There are four reasons for monitoring serum levels dose titration understand interactions limit adverse effects check compliance. [Pg.690]

Now we consider situations in which transformation of the organic compound of interest does not cause growth of the microbial population. This may apply in many engineered laboratory and field situations (e.g., Semprini, 1997 Kim and Hao, 1999 Rittmann and McCarty, 2001). The rate of chemical removal in such cases may be controlled by the speed with which an enzyme catalyzes the chemical s structural change (e.g., steps 2, 3 and 4 in Fig. 17.1). This situation has been referred to as co-metabolism, when the relevant enzyme, intended to catalyze transformations of natural substances, also catalyzes the degradation of xenobiotic compounds due to its imperfect substrate specificity (Horvath, 1972 Alexander, 1981). Although the term, co-metabolism, may be used too broadly (Wackett, 1996), in this section we only consider instances in which enzyme-compound interactions limit the overall substrate s removal. Since enzyme-mediated kinetics were characterized long ago by Michaelis and Menten (Nelson and Cox, 2000), we will refer to such situations as Michaelis-Menten cases. [Pg.750]

If there are several AP minima of close energy, then at low temperatures one should take into account two-phonon-assisted transitions between these minima. In Ref. [15] (see also Ref. [14]) it was found that the rate of these transitions depends on temperature as 7 3. However, as it was already mentioned above, in Ref. [9] it was found that the contribution of the two-phonon-assisted transitions between different Jahn-Teller minima of the AP to the ZPL width at low temperatures is described by the T5 law. Note that an increase of the Jahn-Teller interaction leads to a decrease of the rate of these transitions. Therefore, in the strong Jahn-Teller interaction limit this broadening mechanism becomes unimportant. [Pg.137]

The essential progress in calculation of transport properties in the strong electron-vibron interaction limit has been made with the help of the master equation approach [104-112]. This method, however, is valid only in the limit of very weak molecule-to-lead coupling and neglects all spectral effects, which are the most important at finite coupling to the leads. [Pg.217]

Starting with a Heisenberg Hamiltonian in which Zeeman and exchange interactions (limited to nearest neighbors) are accumulated, the susceptibility is derived as follows ... [Pg.92]

In this approach, we consider the evolution of a system of particles described by means of the generalized HF equations as the interparticle interaction is turned on, starting from a single Slater determinant. The determi-nantal state corresponding to the zero-interaction limit provides an initial condition for solving the generalized HF equations within the n-particle picture. The states which evolve out of this procedure are known to satisfy the Pauli principle in the zero-interaction limit, and the generalized HF procedure to be described below maintains the correct symmetry as well as the requirements of the exclusion principle. [Pg.93]

Equation (4) presents a commonly used ET model that is a special case of Eq. (1) [5,35,36,38,39,53-58]. Here only a single vibrational (nuclear) mode is active, and it is in the high-temperature (or classical) limit. In this model all the reactants that become products pass over the top of the reaction barrier (an activated process), and none of the reaction occurs by nuclear tunneling through the barrier. However, not all of the reactants that reach the top of the barrier actually become products many simply relax without reacting (nonadiabatic or weak-interaction limit). [Pg.7]

Table S.2. Sphere-sphere interactions, limiting forms... Table S.2. Sphere-sphere interactions, limiting forms...
Fig. 1. Optical transitions in charge-transfer complexes in the weak (A) and strong (B) interaction limits. Fig. 1. Optical transitions in charge-transfer complexes in the weak (A) and strong (B) interaction limits.
The capabilities of antibody microarray technology are similar to those for DNA array methods selectivity of immunoreagents in complex protein lysates rapid, massively parallel analysis of proteins small sample volume requirement and automation and compatibility with DNA microarray technologies (in hardware, software, and bioinformatics) also, native proteins are analyzed, which affords information on specific structure and protein-protein interactions. Limitations of this... [Pg.63]

Figure 184 External quantum EPH efficiency data taken from Fig. 181 and represented by a < eph pl°t n order to fit with the trip 1 e t—charge-ca i rier interaction limit for triplet exciton decay according to Eq. (337) (solid lines). After Ref. 304. Copyright 2002 American Physical Society, with permission. Figure 184 External quantum EPH efficiency data taken from Fig. 181 and represented by a < eph pl°t n order to fit with the trip 1 e t—charge-ca i rier interaction limit for triplet exciton decay according to Eq. (337) (solid lines). After Ref. 304. Copyright 2002 American Physical Society, with permission.
S. L. Shenoy, W. D. Bates, H. L. Frisch, G. E. Wnek. 2005.Role of chain entanglements on fiber formation during elecfrospinning of polymer solutions good solvent, nonspecific polymer-polymer interaction limit. Polymer, 46. pp. 3372-3384. [Pg.144]

The thermal conductivity of a pure metal is lowered by alloying, whether the alloy formed is a single phase (solid solution) or multiphase mixture. There are several reasons for this. First, electrons are scattered by crystal imperfections and solute atoms (electron-defect scattering). Second, a substantial portion of the thermal conductivity in alloys, in contrast to that of pure metals, is by phonons, Kph (phonons are the sole contribution in electrically insulating solids) and phonons are also scattered by defects. Finally, electron-phonon interactions limit both Kei and Kp. ... [Pg.251]

The equilibrium configuration of the reactants in the zero-interaction limit is located at A = 0 with Ga,eq = 0. At the transition state, Ga = Gb so that X and the free energy of activation in the zero-interaction limit are given by Eqs 5a and 5b, respectively. [Pg.1249]

AG° = 0. As is evident from Eq. 13 and Figure 4, the two coordinates are not linearly related except at very large i/ab. In the very weak interaction limit (diabatic curves, Hjo = 0) no electron density is transferred until X = 0.5 when the electron suddenly jumps from the donor to the acceptor. In this case Cb is not a continuous function of X. instead Cb = 0 for all A < 1/2 and Cb = 1 for X > 1/2. As 7/ab increases, charge density is transferred more gradually (with more delocalization present in the initial reactant configuration) and Cb approaches linearity in X when //ab > X. Figure 4 shows that for typical symmetrical Class II systems most of the charge density is transferred between X = 0.4-0.6. [Pg.1252]

In the weak-interaction limit, the exchange mechanism can be described in terms of thermodynamic quantities, according to a classical approach which parallels that for nonadiabatic electron transfer (see Eqs. (1) and (2)) [59-63]. [Pg.3276]


See other pages where Interacting limit is mentioned: [Pg.1072]    [Pg.439]    [Pg.158]    [Pg.212]    [Pg.455]    [Pg.377]    [Pg.265]    [Pg.378]    [Pg.45]    [Pg.229]    [Pg.106]    [Pg.165]    [Pg.61]    [Pg.63]    [Pg.188]    [Pg.390]    [Pg.236]    [Pg.149]    [Pg.483]    [Pg.243]    [Pg.44]    [Pg.166]    [Pg.1627]    [Pg.29]    [Pg.136]    [Pg.1266]    [Pg.1267]    [Pg.1278]    [Pg.2164]    [Pg.325]   


SEARCH



A posteriori Brillouin-Wigner correction to limited multi-reference configuration interaction

Brillouin-Wigner perturbation theory and limited configuration interaction

Coulomb interactions limits

Dipolar interactions, dynamic range limitation

Electrostatic interactions high charge density limit

Full configuration interaction limit

Half-space interaction limit

Interaction confidence limits

Limited configuration interaction

Limited configuration interaction Brillouin-Wigner perturbation

Limited configuration interaction expansion

Limited configuration interaction multi-reference Brillouin-Wigner

Limited configuration interaction perturbation theory

Multi-reference Brillouin-Wigner perturbation theory for limited configuration interaction

Orbital interaction theory limitations

Spin-Interactions and the Non-relativistic Limit of Electrodynamics

Transport limitation by reaction-diffusion interaction

© 2024 chempedia.info